1. Technical Field
The present invention relates to a liquid crystal device and an electronic apparatus.
2. Related Art
As the liquid crystal device, for example, an active driving type liquid crystal device in which a transistor for switching and controlling a pixel electrode is provided for each pixel, is known. The liquid crystal device is used, for example, as a liquid crystal light bulb of a liquid crystal projector as an electronic apparatus.
The liquid crystal device includes an element substrate, a counter substrate disposed opposite to the element substrate, and a liquid crystal layer interposed by the element substrate and the counter substrate. In the element substrate, the transistor and a light shielding layer for shielding light from the liquid crystal projector to the transistor are provided.
For example, in the liquid crystal device described in JP-A-2003-131261, a method of shielding light toward the transistor is disclosed, by providing the transistor on a substrate of a pixel region and providing a first light shielding film and a second light shielding film between the substrate and the transistor (active layer). In particular, as the amount of light of the liquid crystal projector increases, it is required to improve light shielding properties.
Even though strong light from a light source is incident to the liquid crystal light bulb, when light is irradiated to the semiconductor layer that constitutes the switching element, a flicker or pixel non-uniformity occurs on the display image by light leakage current, and this results in display quality degradation. Thus, improvement in the light shielding properties of incident light has been achieved from the related art. In recent years, there has been a case where the amount of light from the light source increases and an inorganic polarization plate having high light reflectivity compared to the related art is used. For this reason, a technique for improving the light shielding properties of the reflected light or the like that is incident from the side from which light of the liquid crystal device is emitted (back surface), has been proposed (for example, refer to JP-A-2004-5302475 and JP-A-2011-238835).
JP-A-2003-131261 discloses a configuration in which a scanning line (gate wiring) that is formed by stacking a metal light shielding film A, an insulating film (metal oxide film or metal nitride film) B, and a metal light shielding film C is disposed in the lower layer of the semiconductor layer of a reverse staggered (bottom gate) type TFT. JP-A-2004-5302475 discloses a configuration in which a first light shielding film and a second light shielding film that interpose an insulating film therebetween are stacked in the lower layer of the semiconductor layer and the potential of the second light shielding film is set to a gate potential or a constant voltage.
In a large liquid crystal device, there is an increasing need for driving using a high frequency driving signal. On the other hand, in a small liquid crystal device, though the arrangement pitch of the pixels is narrow, a light shielding region tends to be narrowed in order to increase the aperture ratio. For this reason, a technique for improving the light shielding properties and decreasing the wiring resistance has been proposed (for example, refer to JP-A-2011-158700). JP-A-2011-238835 discloses a configuration in which a scanning line that is formed by stacking the three layers of a metal film is disposed in the lower layer of the semiconductor layer.
However, in JP-A-2003-131261, although the configuration of the light shielding film in the pixel region is disclosed, the configuration of the light shielding film in the peripheral region around the pixel region is not disclosed. Further, when light is incident to the transistor in the peripheral region, there is a problem that light negatively affects the characteristics of the transistor such as the change in the characteristics of the transistor or the like.
In addition, in JP-A-2004-5302475 and JP-A-2011-238835, since two layers of the light shielding layer are insulated from each other, the wiring resistance of the scanning line is not considered. Further, in JP-A-2011-158700, since the light shielding layer (scanning line) is made of the three layers of a metal film that are stacked being in contact with each other, there is a concern that the light shielding properties are insufficient compared to a case where a layer having a different refractive index such as an insulating film or the like is interposed between the light shielding layers. Therefore, there is a demand for a display apparatus capable of improving the light shielding properties compared to the related art and decreasing the wiring resistance of the scanning line.